Creating a homogenized earthquake catalog for Algeria and mapping the main seismic parameters using a geographic information system

Abstract

A homogeneous earthquake catalog is an essential instrument to study earthquake occurrence patterns, employing diverse engineering applications. In this paper, we describe a series of compilation and processing steps to compile an updated earthquake catalog for Algeria, a North African country with relatively high seismic activity. The procedure consisted of several steps. First, a range of reliable catalogs were considered; second, the data was integrated and refined; third, magnitudes are homogenized from different kinds of magnitudes into moment magnitude (Mw); declustering is then performed; and, finally, the magnitude-year completeness was estimated. The resulting Algeria catalog is bounded by the geographical limits (19°–38.5° N and 9.5° W − 12.5° E), and covers the 1960–2020 period. It includes 4021 seismic events, reported up to Mw 7.1. We also calculate a set of seismic parameters, namely Mmax and b-value, and mapped them using a geographic information system. Thus, the territory is divided into cells based on different grids to conduct the analysis. The results of the seismic parameters mapping are discussed, highlighting significant details. Several cells presented a Mmax between 6.0 and 7.1. Regarding the b-value, two regions (Oran and Constantine) presented a high b-value, implying low-stress areas, and three regions (Algiers, Batna, and Chlef) a low b-value (0.65− 0.85), suggesting high-stress areas. Finally, we suggest some recommendations for future seismic hazard assessment studies.